FIG. 1 is a flow chart depicting a conventional method 10 for fabricating side shields for a conventional magnetic recording transducer. For simplicity, some steps are omitted. The conventional method 10 typically starts after a pole, such as a perpendicular magnetic recording (PMR) pole has been provided in a nonmagnetic layer, such as aluminum oxide. For example, a damascene process that forms a trench in the aluminum oxide layer, deposits nonmagnetic side gap/seed layers, and deposits magnetic pole layers may be used. In addition, the portion of the magnetic material external to the trench may be removed, for example using a chemical mechanical planarization (CMP) process. A wet etch mask is provided, via step 12. The wet etch mask exposes part of the nonmagnetic layer around the pole near the location at which the air-bearing surface (ABS location) is to be formed. The portion of the nonmagnetic layer exposed by the wet etch mask is also exposed by any other masks remaining from the pole formation process.
The exposed aluminum oxide is wet etched, via step 14. Thus, a trench is formed around a portion of the pole near the ABS location. Note that side gap layers may remain after the aluminum oxide etch in step 14. In some cases, a side gap layer (or an additional side gap layer) may be deposited after step 14. The seed layer for the side shield is deposited, via step 16. A mask for the side shield is deposited, via step 18 and the side shield deposited, via step 20. The mask used for depositing the side shield may also be removed in step 20. Further, the exposed portion of the side shield seed may also be removed. Aluminum oxide is deposited, via step 22. Thus, the trench formed by the wet etch is refilled. The transducer may then be planarized, via step 24. Formation of the transducer may then be completed.
FIG. 2 depicts plan and air-bearing surface (ABS) views of a portion of a conventional PMR transducer 50 formed using the conventional method 10. The conventional transducer 50 includes an underlayer 52, aluminum oxide layer 54 in which the pole is formed, Ru side gap layer 56 which is deposited in the trench (not shown) is also shown. The pole 58, seed layer 60, side shield 62, and aluminum oxide layer 64 are also shown. Thus, using the conventional method 10, the side shield 62 may be formed.
Although the conventional method 10 may provide the conventional transducer 50, there may be drawbacks. The performance of the conventional transducer 50 may be compromised. In particular, fabrication using the method 10 may result in magnetic material at unexpected and/or uncontrolled locations. For example, the magnetic transducer 50 may include magnetic inclusions 66. The inclusions may be present due to the removal of excess side shield material after step 20. In addition, undercuts 68 are shown. These undercuts may be formed due to the mask provided in step 18. The mask may have a BARC or other mask underlayer that is formed for mask formation. The mask underlayer that tends to be undercut. Thus, when the side shield materials are deposited, the undercut may be filled, forming inclusions 68. Thus, magnetic material may reside at locations 66 and 68, which are inadvertent and uncontrolled. In addition, parts (not shown) of the seed layer 60 that are far from the pole 58 may be difficult to remove. There may be some portion of the magnetic side shield material residing on these remaining parts of the transducer 10. Thus, additional unwanted magnetic material may remain at the ABS of the conventional magnetic transducer 50. Like the inclusions 66 and 68, this additional magnetic material is undesirable.
Accordingly, what is needed is an improved method for fabricating a transducer.